Identification of new species of Enterococcus faecium with probiotic properties from traditional Iranian dairy sources

Finding new probiotic strains can help in achieving nutritional and therapeutic goals due to their consumption. The purpose of this study was to isolate probiotics from traditional dairy products of cities in Isfahan. Lactic acid bacteria were isolated from traditional dairy sources. Probiotic characteristics of the isolates was evaluated by carrying out bile salt tolerance tests, acid tolerance tests and checking their hemolytic activity. Then, the antimicrobial activity of probiotic isolates was determined against Escherichia coli and Pseudomonas aeruginosa. In order to definitively identify the isolates, colony PCR was performed using general primers designed in the 16S rRNA gene, and the gene sequences of the strains were registered in the world bank. Three strains of Enterococcus faecium were isolated and identified from the dairy products that were able to grow in the pH values of 3 and 4.5 as well as the ability to grow in 0.3% bile salt. All the strains had antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa, without any significant differences, with inhibition zones diameters of 12 to 16 mm. The isolated strains were registered in NCBI database with the accession numbers MZ853942, MZ854204, and MZ902025. Considering the confirmation of the probiotic properties of the local isolated strains, it is recommended to use them in the production of food complements and probiotic starter cultures.